JP2006027373A - Air bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air bag, in particular a side airbag, equipped with an enhanced air-tightness without impairing the characteristic of its sewn part using a simple procedure. <P>SOLUTION: The air bag, in particular the side air bag, is structured so that a plurality of body panels are sewn together, in which the sewn part consists of sewing threads and an easy-to-melt material, wherein the ratio by weight of the sewing threads A to the easy-to-melt material B having a melting point below 200°C, A:B, should preferably be 1:5 through 5:1, and the sewn part is generated with sewing threads having a strength no less than 6 cN/dtex at a stitch number of 2-10 sticthes per cm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an airbag for protecting an occupant in the event of a vehicle collision, and more particularly to an airbag having excellent airtightness and suitable for side collision protection.

Airbag systems have become widespread as safety devices for protecting passengers in vehicles, and there are an increasing number of mounting parts for driver seats, passenger seats, side impact protection, and rear seats, and the protection function for passengers is increasing. In particular, an airbag that protects an occupant from an impact at the time of a side collision, that is, an airbag for side collision protection (hereinafter referred to as a side airbag) has been put into practical use as a means for improving safety for the occupant. Against this background, there is a case where a vehicle with a high vehicle height, excellent mobility, and high versatility is preferred, and the vehicle rolls over due to an accident. In the event of a rollover of a vehicle, that is, a rollover, it is necessary to protect the occupant for a long time of several seconds, and the air bag must have high airtightness.

For this reason, in a rollover-compatible airbag, the body panel is provided with a coating layer for imparting airtightness, and means for preventing gas leakage from the seam is also provided at the stitched portion.
For example, Patent Document 1 (Japanese Patent Laid-Open No. 4-197848) discloses applying a sealing material for sealing from the upper surface side of the outer peripheral seam portion of the airbag.
Further, in Patent Document 2 (Japanese Patent Application Laid-Open No. 10-102029), a joint portion made of a reactive polyurethane-based hot melt adhesive is reinforced by stitching, and the hot melt adhesive is remelted and joined by stitching. A method for sealing a gap generated in a part is proposed.

All of these methods use a compound with excellent adhesiveness in the stitched portion to close the seam, but the addition of the stitching and the adhesive compound is a separate process, making the process complicated, and the compound The coating device is required, and the total cost is increased.
Further, Patent Document 3 (Japanese Patent Application Laid-Open No. 10-166978) proposes a method of sewing together a sheet-like material at the stitched portion of the outer edge portion in an airbag made by stitching the outer edge portion of the main body cloth. Has been. According to this method, the application of the sheet material can be performed simultaneously with the stitching of the outer peripheral portion, so a new process is not required, but it is necessary to select a sheet material that is easy to follow along the outer peripheral portion, and the material and shape of the sheet material Depending on the amount of use, the rigidity of the entire outer periphery stitched portion tends to increase, and the folding volume of the airbag tends to increase.
Japanese Patent Laid-Open No. 4-197848 Japanese Patent Laid-Open No. 10-102029 JP-A-10-166978

  The present invention is an innovative technique that can improve the airtightness of the stitched portion by a simple process, which is impossible with these prior arts, and is reasonably airtight without impairing the characteristics of the stitched portion. It is an object of the present invention to provide an air bag that can maintain airtightness for a long time even when a vehicle rolls over in the event of a collision, especially in a side airbag. .

The present invention relates to a method for enhancing airtightness of an air bag body by stitching together an easily meltable material together with a sewing thread and closing the seam by melting the easily meltable material after stitching. It is.
That is, the present invention

(1) An airbag in which a plurality of main body panels are stitched, wherein the stitched portion is stitched with a sewing thread and a readily meltable material, and the stitches are sealed by melting the meltable material after stitching. An airbag, characterized by
(2) In the above (1), the weight ratio of the sewing thread (A) and the easily meltable material (B) is in the range of (A) :( B) = 1: 5 to 5: 1. The described airbag,
(3) The airbag according to (1) or (2), wherein the melting point of the easily meltable material is 200 ° C. or less,
(4) The airbag according to any one of (1) to (3) above, wherein the stitched portion is stitched with a stitching thread having a strength of 6 cN / dtex or more at a needle operation number of 2 to 10 stitches / cm,
(5) The airbag according to any one of (1) to (4), wherein the airbag is a side protection airbag that is mounted around a window portion of a vehicle.
It is about.

  According to the present invention, it is possible to impart airtightness to an airbag without complicating complicated processes and without damaging the characteristics of the stitched portion, and in particular, for rollover that needs to maintain airtightness for a long time. A satisfactory side airbag can be provided in a short process.

  The airbag of the present invention is an airbag in which a plurality of panels are stitched, and it is important that the stitched portion is stitched together with a sewing thread and an easily meltable material. The sewing thread bears the strength of the seam of the stitched portion, and the seam can be closed by melting the easily meltable material, and the joining strength and high airtightness of the main body panel can be ensured only by the stitching process.

  The combined form of the sewing thread and the easily meltable material may be any form as long as it can be supplied at the time of sewing the main body panel. For example, 1) A thread, tape-like, slit yarn-like easily meltable material is used as the sewing thread. Integrate by blending, twisting, winding, drawing, etc. 2) Covering the surface of sewing thread with melt, water dispersion, powder, etc. of easily meltable material 3) Sheet, film What is necessary is just to use what is obtained by methods, such as winding a sewing thread with a shape, a nonwoven fabric form, and a net-like easily meltable material.

  If you want to further improve the airtightness obtained by stitching the sewing thread and the easily meltable material, you can do it at the same time as sewing, for example, by sandwiching the easily meltable material between the body panels just before stitching, Alternatively, a method of sewing an easily meltable material, a method of covering the upper surface of the stitching portion with an easily meltable material, and the like may be used in combination.

  The easily meltable material used in the present invention may be sewn together with a sewing thread, and only needs to be able to close the seam by heating after stitching, preferably has a melting point of 200 ° C. or lower, more preferably 120 to 200 ° C., Most preferably, a thermoplastic material in the range of 150 to 200 ° C is used. When the melting point exceeds 200 ° C., there is a possibility of physical damage to the sewing thread and the main body panel during the heat treatment. Further, the easily meltable material is preferably excellent in adhesion to the main body panel, the covering material of the main body panel, the sewing thread, and the like, and a material suitable for each material to be used may be selected. For example, nylon 6 / 66, 6/10, 6/12, 6/66/12, etc., polyamide copolymer resins (including modified polyamide resins), aliphatic / aromatic copolymer polyester resins, polyurethane resins (halogen-modified resins) 1 type or 2 types or more may be used from among polyolefin resin (including ionomer resin), ethylene / vinyl acetate copolymer resin, and the like. However, the present invention is not limited to these.

In the present invention, the seam formed by the easily meltable material and the sewing thread is heated to melt the easily meltable material, thereby closing the seam and obtaining high airtightness. As a means for melting the easily meltable material, it is sufficient that the material can be efficiently melted without impairing the characteristics of the sewing thread and the main body fabric around the stitched portion. Heating, 2) high frequency heating, 3) dielectric heating such as ultrasonic waves and microwaves, 4) resistance heating, induction heating such as infrared rays, 5) laser heating, 6) friction melting, and the like may be used. Also, the heating conditions may be selected according to the melting point of the easily meltable material used, the form of the material (thickness, shape), etc. For example, in the case of external heating, 120 to 200 ° C. × 0.5 to 2 The melting efficiency can be further improved by the heating press.
In addition, in the present invention, a foaming agent that expands by heating, a thermally expandable microcapsule, etc. are mixed and used together with an easily meltable material, so that the easily meltable material melts and seals the seam. Or the physical filling effect by expanding can be acquired. That is, the apparent amount of the easily meltable material can be increased, and the seam hole can be effectively shielded with a small amount. Materials that induce foaming by heating include azo compounds such as azodicarbonamide and azobisisobutyronitrile, hydrazide compounds such as p-toluenesulfonyl hydrazide, p and p-oxybisbenzenesulfonyl hydrazide, and p-toluene. One or more selected from organic compounds typified by azide compounds such as sulfone azide, and inorganic foaming agents typified by ammonium carbonate, sodium bicarbonate, ammonium nitrite, etc. It may be used while taking into consideration the foaming property, melting point, etc. of the material.

  In the present invention, the weight ratio of the sewing thread (A) to the easily meltable material (B), (A) :( B) is in the range of 1: 5 to 5: 1, preferably 1: 3 to 3: 1. Thus, the airtightness of the airbag can be further improved without impairing the effects of the present invention, that is, the characteristics of the stitched portion. The ratio of (A) :( B) may be selected according to the airbag specification, stitched part, inflator specification, etc. If the seam is large due to the base fabric specification, etc., the ratio of (B) will be increased to make it dense When a base fabric is used or a covering material that imparts airtightness is applied, the ratio (B) may be lowered.

  The strength of the sewing thread used for the suturing according to the present invention is preferably 6 cN / dtex, preferably 7 cN / dtex in order to secure the strength of the stitched portion. In the present invention, since the sewing thread and the easily meltable material are combined and stitched together, the composite thread to be used tends to have an apparent thickness. Therefore, the strength of the sewing thread that supports the strength of the stitched portion is preferably higher. In addition, the number of stitches of the sewing thread in the stitching portion should be in the range of 2 to 10 stitches / cm, preferably 4 to 10 stitches / cm, and the stitching specification to reduce the size of the stitch hole generated by the stitch misalignment should be kept. desirable.

  The sewing specification of the stitching portion of the present invention may be performed by stitches that are applied to a normal airbag such as main stitching and double chain stitching. The thickness of the sewing thread may be 700 dtex (equivalent to 20th) to 2800 dtex (equivalent to 0th). When a plurality of stitch lines are required, the distance between the stitches is about 2 to 8 mm, and a multi-needle type sewing machine may be used. However, a single-needle sewing machine may be sewn multiple times.

  The suture used in the present invention is composed of a normal sewing thread and an easily soluble material, and since the overall thickness is thick, it is preferable to use a sewing machine needle with a large count, that is, a sewing machine with a large needle hole. A needle should be used. In addition, the surface of needle holes and other surfaces is smoothened by metal coating such as chrome and titanium, and Teflon (registered trademark) treatment, and the composite thread is easy to pass through the needle holes and sewing machine guides. It is preferable to sew while applying the treatment agent in order to make the present invention easier to implement, and even if a method such as cooling the needle hole is used so that the composite yarn does not stick due to friction. Good. Further, a sewing jig such as a binder, a holder, or a trumpet may be used in order to integrate the sewing thread and the easily meltable material immediately before stitching by drawing, winding, pinching, and the like.

  The sewing thread used for sewing may be appropriately selected from what is generally called a synthetic fiber sewing thread and those used as industrial sewing threads. For example, nylon 6, nylon 66, nylon 46, nylon 6T, nylon 9T, There are polyester, vinylon, aramid, carbon, glass and the like, and any of spun yarn, filament twisted yarn, and filament resin processed yarn may be used.

  The panel used for the airbag body base fabric in the present invention is a covering material usually used for airbags to give heat resistance, airtightness, etc., for example, silicone resin or rubber, polyurethane resin or rubber (silicone modified) 1 type or 2 types or more selected from chlorine-containing rubbers such as chloroprene rubber and hypalon rubber, fluorine-based rubber, polyester-based resin or rubber, polyamide-based resin or rubber, etc. good.

  The methods for applying these coating materials to the main fabric are 1) coating method (knife, kiss, reverse, comma, etc.), 2) dipping method, 3) printing method (screen, roll, rotary, etc.), 4) Processing methods such as laminating and 5) spraying may be used. The properties of the coating material may be any of solvent-based, solvent-free, emulsion-based, aqueous-based, or mixed solutions thereof, fine powder, film or sheet.

  In addition, the coating material includes various additives usually used for improving processability, adhesion, durability, weather resistance, etc., such as a crosslinking agent, a reaction accelerator, a reaction retarding agent, a heat stabilizer, Antioxidants, light stabilizers, anti-aging agents, lubricants, smoothing agents, anti-blocking agents, pigments, water repellents, oil repellents, concealing agents such as titanium oxide, gloss imparting agents, flame retardants, plasticizers, etc. One kind or two or more kinds may be selected and mixed for use.

  Application | coating of the coating | covering material to the base fabric for main body panels may laminate | stack the same or different 2 or more types of coating | covering materials. Also, a second covering material that is excellent in smoothness against friction with glass or the like as a top layer so that the airbag can be easily deployed along the side window, for example, an inorganic filler such as magnesium salt or calcium salt A covering layer having a two-layer structure may be formed by stacking a covering material including a layer on a first covering material as an undercoat layer. The covering material may be interposed on at least one surface of the main body base fabric, a gap portion of the base fabric, or a gap between fiber yarns.

  In addition to the above-mentioned various additives, various pretreatment agents for improving adhesion to the base fabric, adhesion improvers, etc. may be added to the covering material, or the surface of the base fabric may be primed beforehand. The pretreatment may be performed. Furthermore, in order to impart heat resistance, aging resistance, oxidation resistance, etc. to the coating agent, after applying the coating agent to the fabric, drying, crosslinking, vulcanization, etc. are performed with hot air treatment, contact heat treatment, high energy treatment (high frequency treatment) , Electron beam, ultraviolet ray) or the like.

Moreover, the base fabric used for the main body panel of the present invention may be any fabric as long as it satisfies the instantaneous impact force at the time of deployment, the airtightness and pressure resistance as a bag body, the folding volume, etc. It is preferable to use a base fabric having a dense structure composed of 500 dtex yarn. The denseness of the base fabric affects the amount of seam deviation that occurs. For example, it is preferable that the fabric has a cover factor of 720 or more, more preferably 800 to 1120. Here, the cover factor (CF) is a parameter representing the density of the woven fabric structure determined by the product of the thickness of the warp and weft (decitex) and the fabric density of the warp and weft (lines / cm). expressed.
CF = Nw × √Dw + Nf × √Df
Here, Dw and Df represent the warp and weft thickness (decitex), and Nw and Nf represent the warp and weft fabric density (lines / cm).
The single yarn thickness of the yarn is preferable, for example, by using a thin yarn of 3.3 dtexi or less because a base fabric having high flexibility can be obtained even at high density.

  The base fabric of the airbag body used in the present invention may be woven by various looms used for producing ordinary industrial fabrics, for example, shuttle loom, water jet loom (WJL), air jet A loom (AJL), rapier loom, or projectile loom may be selected. In the present invention, in addition to a normal woven fabric composed of warps and wefts, a triaxial woven fabric, a tetraaxial woven fabric, or the like that has improved the mechanical isotropy of the woven fabric may be used. Moreover, you may use the bag woven structure partially connected by the woven structure with the Jacquard loom. The woven structure may be any of plain weave, twill weave, satin weave, oblique weave, lattice weave (ripstop weave), silk weave, or a combination thereof.

  Further, the fiber yarn constituting the main body fabric of the present invention is not particularly limited. For example, nylon 6, nylon 66, nylon 46, nylon 610, nylon 612 or the like alone or by copolymerization or mixing thereof. Aliphatic polyamide fiber obtained, copolymerized polyamide fiber of aliphatic amine and aromatic carboxylic acid represented by nylon 6T, nylon 9T, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc. Polyester fibers obtained by copolymerization, mixing, chlorine fibers such as vinylidene or polyvinyl chloride, fluorine fibers containing polytetrafluoroethylene, polyacetal fibers, polysulfone fibers, polyphenylene sulfide fibers (PPS) , Polyether ether ketone (PEEK) fiber, polyimide fiber, polyetherimide fiber, cellulose fiber including high strength rayon, vinylon fiber, acrylic fiber, silicon carbide fiber, alumina fiber, glass fiber, carbon fiber, depending on the case May be appropriately selected from metal fibers typified by steel.

  These fiber yarns have various additives that are commonly used to improve spinnability, processability, and material durability, such as heat stabilizers, antioxidants, light stabilizers, anti-aging agents, One or more of a lubricant, a smoothing agent, a pigment, a water repellent, an oil repellent, a concealing agent such as titanium oxide, a gloss imparting agent, a flame retardant, and a plasticizer may be used. Moreover, you may give processes, such as twisting, a bulky process, a crimping process, and a winding process depending on the case. Furthermore, the form of the yarn is not particularly limited, such as filaments of long fibers, spun yarns of short fibers, and composite yarns thereof.

The specifications, shape, and capacity of the airbag according to the present invention may be selected according to the site to be disposed, the application, the storage space, the impact absorption performance with the contact object, the output of the inflator, and the like.
Also, rollover compatible airbags require extremely high airtightness, so there is usually no exhaust hole for gas exhaust, but when high energy absorption is required when the occupant abuts One or a plurality of exhaust holes, for example, a circle having a diameter of about φ10 mm to φ40 mm or a hole having an area equivalent thereto may be provided, and a reinforcing cloth may be joined around the exhaust holes. Furthermore, you may provide parts, such as an auxiliary member for promoting the expansion | deployment performance of an airbag, and a baffle cloth for controlling the gas flow inside an airbag.

  In the present invention, depending on the characteristics of the inflator used, a heat-resistant protective cloth or a mechanical reinforcing cloth for protecting the airbag body base cloth from the hot gas from the inflator may be provided. These protective cloths and reinforcing cloths may be made of heat-resistant materials such as heat-resistant fiber materials such as wholly aromatic polyamide fibers, wholly aromatic polyester fibers, polyimide fibers, and fluorine-containing fibers. A base fabric such as a fabric using a thread thicker than a main body base fabric which is the same as or separately prepared from the airbag main body may be coated with a heat resistant material, or may be used without a coating material. .

The bag can be folded using a bellows fold, folding screen-like zipper fold, roll-up, or a combination of these. Bending, roll winding, etc. may be adopted.
The present invention relates to a method for obtaining a high airtightness of a side collision protection airbag.For example, a front seat for a driver seat and a passenger seat, a headrest bag for rear end collision protection, a knee bag, a foot bag, Pedestrian protection airbags, infant protection (child seat) mini bags, air belt bags, passenger cars, trucks / buses, motorcycles, etc. It may be applied to other uses such as airplanes, other transportation means, amusement park facilities, etc.

Hereinafter, the present invention will be described more specifically based on examples. In the examples, the performance evaluation of the airbag body is performed by the following method.
(1) Airtightness of airbag An inflator (tank pressure 200 kpa, helium gas type inflator manufactured by Daicel) was fixed to the inflator insertion portion 10 of the airbag together with a fixing bracket, and the airbag was deployed at room temperature. The maximum internal pressure of the airbag and the internal pressure retention rate (%) 5 seconds after the start of deployment were determined.
(2) Comparison of manufacturing process The time required for the airbag sewing process and the seam sealing process was measured, and the time when sewing with only the sewing thread was set as 100.

Example 1
A plain woven fabric having a weaving density of 23 yarns / cm and a weaving density of 23 yarns / cm was prepared using nylon 66 fiber 350 dtex / 144 f (yarn strength 8.6 cN / dtex). This woven fabric was scoured and heat-set, and then a polycarbonate type polyurethane resin was applied to one side of the woven fabric at 40 g / m ² (in terms of solid content). The weave density was 24.5 pieces / cm in both warp and weft.
Next, two base fabrics were cut into the shape shown in FIG. 1 as the main body base fabric of the airbag. The overall size of the airbag is 165 cm in length and 55 cm in height, and the cut cloth 2 has a shape in which the central portion of the cut cloth 1 is deleted along the joining line. The two pieces are overlapped with the coated surfaces aligned, and the stitches of the outer peripheral part (3) and the inner part (4a to 4d) are used as the sewing thread (upper and lower) and the eighth thread of nylon 66 fiber (equivalent to 940 dtex) A tape-like thread obtained by slitting a film (thickness: 0.1 mm) made of nylon 6/66/612 copolymer polyamide resin (melting point: 125 ° C.) as an easily meltable material into a width of 4 mm. Using. The tape-like thread was previously wound around the sewing thread for the upper thread and integrated. In the obtained composite yarn, the weight ratio of the sewing yarn to the easily meltable material was 2.5: 1. 26th hand is used as the sewing needle, 2 rows of double chain stitches on the outer circumference and 1 row of main stitches on the inner side are sewn at 5 stitches / cm, respectively, and then the airbag is heated to 140 ° C by hot air. For 1 minute.
The deployment test of the obtained airbag was conducted. The internal pressure retention rate of the airbag is excellent, and the manufacturing process is slightly longer than that in the case of sewing only (Comparative Example 2), but the process can be significantly simplified compared to the conventional method (Comparative Example 1).

Comparative Example 1
In Example 1, a polyurethane-based hot-melt resin is applied to the stitching line of the outer peripheral part (3) and the inner part (4a to 4d) on the coat surface of the main body base cloth 1, and the main body base cloth 2 The coated surfaces were overlapped, and the two main body base fabrics were lightly crimped. After that, it was sewn only with a sewing thread in accordance with Example 1, and after the suturing, it was crimped at 160 ° C. for 2 minutes. The stitched portion of the obtained bag had a resin thickness of about 1 mm and a width of about 20 mm.
Although the internal pressure retention rate by the development test is excellent, the manufacturing process takes a long time.

Comparative Example 2
In Example 1, the stitched portions of the outer peripheral portion (3) and the inner side portions (4a to 4d) were stitched only with the sewing thread, and a deployment test of the obtained airbag was performed. Although the manufacturing process is shortened, the internal pressure retention rate is low, and it is not suitable for rollover.

Explanatory drawing before the expansion | deployment which looked at the airbag which becomes this invention from the side window part. The AA sectional view taken on the line of FIG. 1 after expansion | deployment. The outer peripheral portion 3 and the hatched portions 4a and 4b indicate melting portions of the easily meltable material.

Explanation of symbols

1, 2, ... Airbag body panel 3 ... Peripheral stitched part of airbag body panel 4a to 4d ... Internal joint part between body panels 5a to 5e ... Inflatable part of airbag 8 ... Melting part of easily meltable material 9 ......... Stitching part with sewing thread and easily meltable material 10 ......... Inflator mounting port

Claims (5)

An airbag in which a plurality of main body panels are stitched, and the stitched portion is stitched with a sewing thread and an easily meltable material, and the stitches are sealed by melting the easily meltable material after stitching. Air bag characterized by. The airbag according to claim 1, wherein the weight ratio of the sewing thread (A) to the easily meltable material (B) is in the range of (A) :( B) = 1: 5 to 5: 1. . The airbag according to claim 1 or 2, wherein the melting point of the easily meltable material is 200 ° C or lower. The airbag according to any one of claims 1 to 3, wherein the stitched portion is stitched with a sewing thread having a strength of 6 cN / dtex or more at a number of stitches of 2 to 10 stitches / cm. The airbag according to any one of claims 1 to 4, wherein the airbag is a side protection airbag to be mounted around a window portion of a vehicle.

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